fix(bug-1735): job memory/CPU usage always read 0 in scheduler replay

Two independent gaps in misc.c/job.c, both silently zeroing every real
job's resource-usage data:

- update_host_runusage() matched worker rusage report resnames
  "cputime"/"mem", but the real worker's collector
  (collect_job_rusages(), xcecd_cgroups.c) sends "cpu_time_sec"/
  "memory_rss" -- the two never matched, so cpu_time/mem_usage stayed
  at their calloc()'d zero for every non-simulated job. Aligned both
  sides, including xce_test's own simulated-worker fixture.
- update_job_rusages() had a standing FIXME: xce_job_runusage_t's
  job-level max_mem/avg_mem/used_mem/cpu_time were never derived from
  the per-host host_runusage[] entries. Added aggregate_job_runusage()
  (sum/max/avg across hosts) and wired it in right after the per-host
  update.

Added test_host_runusage.c (standalone unit test, mirrors
resval_typeresolve_unit_test's isolation pattern) plus the
controller_unit_test stub aggregate_job_runusage() needs since that
target excludes the real misc.c.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019QxaSzHRB7pmYFp4cVnwkA

src/controller/testsuite/test_commit_barrier_reply.c

@@ -197,6 +197,7 @@ int update_pids(job_pidinfo_t **i, int n, int *p)
 { (void)i; (void)n; (void)p; return 0; }
 int update_pgids(job_pidinfo_t **i, int n, int *p)
 { (void)i; (void)n; (void)p; return 0; }
+void aggregate_job_runusage(xce_job_runusage_t *r) { (void)r; }
 int on_scheduler_join(cluster_t *c) { (void)c; return 0; }
 int add_apiserver(cluster_t *c, char *n, endpoint_t *e)
 { (void)c; (void)n; (void)e; return 0; }